


Tentacles

by omgbubblesomg



Series: 31 fics in 31 days [12]
Category: Supernatural
Genre: #savetheplanet, Anal Sex, Bottom Castiel, Bottom Dean, Bottom Sam, Dean is Not Amused, Dubious Consentacles, Kinktober 2017, Other, Tentacles, Underwater Sex, an attempt is made at being biologically accurate
Language: English
Status: Completed
Published: 2017-10-11
Updated: 2017-10-11
Packaged: 2019-01-16 05:25:18
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 2,154
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12336345
Author URL: https://archiveofourown.org/users/omgbubblesomg/pseuds/omgbubblesomg
Summary: Sam, Dean and Cas are stuck in a lake when their boat fails. So all they have to do is swim to shore. But something in the depths isn’t quite so keen on the idea.





	Tentacles

**Author's Note:**

> Kinktober Day 12: Master/slave; **tentacles** ; hand-jobs
> 
> This one feels a little long to be in the "short hot PWP category" but EH.
> 
> The POV is Cas, and he's totally cool with everything. But the trigger warning is for Dean and Sam who are... not quite as cool with the situation.

“This is a terrible idea,” Castiel grumbled, but he stripped off and followed the Winchesters over the side of the boat and into the murky lake. They had broken down right in the middle and of course nobody had thought to bring oars, so swimming was the only available option.

Sam and Dean could have easily pulled ahead, but they slowed their strokes so Castiel could keep up. Newly human, he wasn’t yet used to the movement of his own body, and propelling himself through water by rotating his arms and kicking his legs was an odd experience.

They took a break after a few minutes, treading easily in place.

“You okay?” Dean wasn’t even breathing hard, and his freckles were winking beneath shiny droplets. Sam’s hair was sticking to his face, sending rivulets of water down his cheeks.

“We should have stayed in the boat,” Castiel muttered, excruciatingly aware of how he must look; red cheeked, with his hair every which way. He fought the urge to cover himself. Even though the water was too dark to see through, he had the distinct impression that his naked body was being watched.

“And get stuck on a haunted lake for the night? No thank you.”

“We don’t know that it’s haunted, Dean.” Sam swatted at something beneath the surface.

“Strange sightings for three weeks straight? I’m going with haunted. Either way, I’m not getting stuck on a freaky lake at night. Especially if we don’t know what’s out here.”

Something brushed Castiel’s leg. Something warm and ridged. He tensed up immediately, but didn’t kick out. There was only one thing in the world that felt like that.

“It’s a Dunwikan,” he said, calmly. “The best thing to do is to not fight it.”

“Say what now?”

“A Dunwikan. It’s not supernatural. Only very rare. It’s in the _Mollusca_ phylum.”

“And how do you know that that’s what we’re dealing with?”

“It has very distinctive suckers,” he replied, not fighting. “I can feel them against my skin.”

“Sorry what did you just— _Something just touched my foot._ ”

“Don’t struggle,” Castiel repeated. “It won’t hurt you if you don’t struggle.” The tentacle around his waist squeezed gently, as if in agreeance. Dean, unsurprisingly, began thrashing wildly.

“Get it off! _Get it off!_ It’s got my leg!”

“Cas!” Sam was panicked, but not fighting nearly as hard as Dean, staring at Cas with wide eyes. “Are you sure? It won’t hurt us?”

“Dunwika are peaceful creatures,” Cas confirmed.

“Peaceful my ass!” Dean snarled. “It’s got my legs spread like a fucking—” Whatever he had been about to say was lost as he was unceremoniously tugged underwater before bobbing back to the surface. He spluttered indignantly. “Cas! Tell your friend to get away from my junk!”

“I hardly think it is interested in your—oh.” The tentacle around his waist had slithered lower, and was now nudging his cock with interest. “This might be a female,” he said weakly. “If she’s in oestrus… that would explain the sightings over the last month.”

“Cas!” Sam was pale, but despite the straining tendon in his neck he appeared to have heeded Castiel’s advice to not fight. “Cas, are we in danger?”

He hesitated. “Not… physical danger,” he concluded. “Though she appears to be more inquisitive than the one I remember last millenium.”

“That’s just… flipping… fantastic… fuck!” A huge grey tentacle emerged from the water beside Dean. At its widest it was as thick as a telegraph pole, tapering off gradually into a rounded point. When it lunged for Dean the concentric inner suckers twitched wetly. “Get this thing away from me!”

Though Sam and Castiel remained only partially restrained, Dean quickly became a mass of slippery grey tentacles, which were winding around his torso and limbs, trying to stop him from fighting. They tugged again, pulling him underwater a second time. When he came back up he started pummelling the thick muscle in front of him. The water bubbled threateningly, but Dean didn’t appear to notice. He’d gotten his hands around one of the tentacles and was attempting to throttle it.

“Dean, _calm down!_ It’s not hurting you!” Sam was tight as a bowstring, but he wasn’t attempting to remove the tentacle that had wrapped around his chest.

The Dunwikan had obviously had enough of Dean’s struggles, and a slender green tentacle rose out of the water and jabbed at his face. Dean tried to swat it away but his hands were getting wrapped up and the green thing jabbed again, shoving into his mouth when he cursed at it.

“Dean!” Sam instantly started battering his own tentacle, trying to swim over to his brother as the green thing pulsed impossibly forward and Dean’s cheeks and throat bulged around it. His eyes went wide and he jerked uselessly before being tugged underwater again. This time he wasn’t brought back up.

“He’s okay,” Castiel tried to reassure Sam.

“Dean!” Sam was fighting properly now, and the water was churning white. He was so frenzied he didn’t notice another green tentacle rise out of the water until it was already buried in his mouth, shoving deep into his throat. Sam bucked, hands scrabbling uselessly at water and unforgiving grey flesh, before he too was sucked under.

A third green tentacle emerged, waving in front of Castiel’s face.

“I suppose you want me to join?” he asked it. He opened his mouth and it slipped in, diving down his throat. Surprisingly, he didn’t feel the urge to gag. It tasted a little salty but apart from the unfamiliar bulge in his throat it wasn’t uncomfortable. The tentacle around his waist tugged and he let himself get pulled underwater.

He blinked against the murk until the green thing in his mouth pulsed and his vision cleared. He found he could see perfectly. Sam and Dean were not far away, suspended in the now clear water, still writhing. Apparently they had not yet noticed that they could breathe normally. The Dunwikan was clever enough to understand their need for oxygen and had devised a method to provide it.

The tentacle around his waist came free, only to tighten around one of his thighs. The suckers pinched playfully at him, tickling, and he grinned around the green obstruction in his mouth. Far below, he could just make out a huge throbbing mountain of grey flesh, from which dozens of green and grey tentacles had emerged.

_Beautiful._

He tried to articulate his thoughts to her, though all that came out was bubbles. She vibrated against his thigh and crept higher, wriggling against his balls and, further, in between his cheeks.

It appeared that Sam and Dean were undergoing a similar treatment, though Dean was still thrashing wildly. When they saw him he waved genially, trying to convey calm. Sam had stopped struggling but Dean didn’t look at all happy to have a thick tentacle wedged between his legs, keeping him spread as the tapered end explored his ass.

It must be a fairly young female, Castiel thought. Maybe even only a few hundred years old, if she was mistaking them for potential mates.

The tentacle between his cheeks probed at him thoughtfully before wriggling inside him, helped by an unknown lubricant and shivering deliciously as it went. Castiel relaxed and let himself enjoy the sensations. Dean was desperately trying to tug his own tentacle away, to little avail. Another thin tentacle was examining Sam, who’s hands had been restrained in front of him, where he couldn’t stop it from pushing into him. Castiel floated upside down, and very much enjoyed how the sunlight trickled through to illuminate the whole scene. The three of them suspended, almost as though they were in mid-air, tentacles coiling around them. The feeling of weightlessness was not unlike flying. It was quite peaceful.

He stretched happily, and the tentacle inside him puffed up slightly, suckers ribbing up against his insides. He reached down to fondle himself, tugging at his cock. It should have been uncomfortable in the water but he found that he could manage a gentle stroke in time with the Dunwikan’s pulsing inside him.

A curious tentacle came up to wrap around his wrist. It wasn’t stopping him, though. It was almost… watching. Learning. After a few seconds it wrapped around his cock, too, imitating his moves. He groaned and nodded. Maybe the Dunwikan knew that they weren’t of the same species, but was trying to learn from them anyway. Castiel directed one of the suckers to cling to the tip of his penis, where it suckled him gently. He groaned around the green tentacle in his throat.

Nearby, extra tentacles went to administer the same treatment to Sam and Dean, who were looking decidedly less comfortable than Castiel felt, even with the addition of extra stimulation. Somehow the Dunwikan was holding them all at the same time. Not only could she learn, but she could use her skills on multiple subjects simultaneously. She was truly enchanting.

Far below, the grey mass moved, and froths of bubbles rose, tickling Castiel as they passed. He wondered if he should be offering some assistance for her pleasure, in return for his own. He patted clumsily at a nearby tentacle, and let the thin end thread through his fingers so he could squeeze it. The tentacle inside him shivered in delight, and from the corner of his eye he could see the same thing happening with the two Winchesters. He tried again, stroking with his free hand, and loved the reaction as it suckered on his inner walls and sped up around his cock. Sam arched, and Dean jerked helplessly. Castiel hoped they were enjoying themselves. They would not have another opportunity like this for the rest of their lifetimes.

The tentacle in his mouth started seeping something sweet, and he sucked at it curiously, still kneading her between his fingers. Dean looked like he was gagging and Castiel tried to reach out for him, though he was too far to make contact.

Perhaps sensing his intent, the Dunwikan pressed a tentacle to Dean’s face, stroking delicately. Dean was helpless to push her away, straining in the wall of muscle that coiled around him. Castiel wondered if he could feel suckers across his entire body. That would be quite interesting. Sam, meanwhile, had his fists clenched but his head was tilted back and his eyebrows furrowed. He looked like he was experiencing an interesting combination of arousal and distress.  Castiel floated closer to get a better view of the thick grey tentacle between his legs. It wasn’t thrusting, but pulsing regularly, in time with the tentacle in Castiel’s body.

Minutes passed and eventually the tentacles began to vibrate erratically. Castiel, foreseeing the Dunwikan’s climax, increased the tempo of his fondling. The sweet secretions in his mouth became even sweeter and he lapped at it with abandon until a high-pitched warble from far below announced her pleasure. The sucker over the tip of his cock latched on and _pulled,_ and he found his own orgasm almost forcibly sucked out of him. He hummed in delight.

The Dunwikan petted him absently and he sensed that he was being propelled upwards. He waved sadly. If only there was some way that he could direct her to one of her own kind. He was sure that there had been a Dunwikan breeding site only a few days away.

The green tentacle slid from his mouth as soon as he hit the surface, leaving only a remnant of the sweet secretion on his tongue. Looking around, Castiel saw that she had delivered him to the very edge of the lake, right next to the jetty. A moment later, Sam spluttered to the surface and, following him, an extremely disgruntled Dean.

A gentle wave came from the depths, propelling their boat to join them on the jetty.

“Thank you!” Castiel called, hoping she could hear.

Dean wobbled onto land, and made his unsteady way to the Impala, muttering curses. He grabbed the grenade launcher, seemed to think better of it, then pulled out the biggest knife in their arsenal. He stalked back to the lakeside.

“Come back here!” he shouted. “Face me when I’m armed why don’t you!” Castiel supressed an eye roll, and noted that Dean never actually put a single toe back into the water.

“Come on,” he said, feeling calm and sated. “Leave her alone.”

 

\-----------

Bonus scene:

 

Dean found Cas at the lake the next day, standing waist-deep in water and talking animatedly. He was holding a bunch of laminated maps, which he was gesturing to carefully. The water was rippling around him, as though there was something just below the surface…

“Cas!” Dean shouted. “Get your ass outta there before you get sucked back into Underwater Horrorland!”

Cas waded out, unashamedly nude. The laminated maps were missing.

Behind him, the lake water churned happily.

 

 

**Author's Note:**

> Dunwikan: Not A Thing. I got the name from The Dunwich Horror (boo Lovecraft) (but yay saving rare species)
> 
> As I was writing this I was worried about authenticity because no one would believe that three people got stranded in a lake and decided to swim to shore, naked.  
> But then I remembered that the fic included a giant tentacle creature in oestrus. So if the only authenticity complaint I get is about the boat then I’m probably doing okay.
> 
> Tune in for Kink Day 13: Medical Play  
> Also yay season 13!  
> Also yay lemons!


End file.
